This invention relates to active carbon adsorbents and methods of preparing same.
There has been great interest of late in storage media suitable for efficient storage of hydrogen above cryogenic temperatures. Hydrogen has become an increasingly attractive energy source, particularly because of its high energy density per unit weight and because it burns cleanly or can be used directly in fuel cells. Hydrogen is also of interest because it can be produced easily by electrolysis of water. Unfortunately, because hydrogen is highly volatile, storage thereof in sufficient quantities has been a major stumbling block to implementation of a hydrogen-based energy infrastructure. Consequently, great effort has recently been directed towards economical ways to store significant quantities of hydrogen.
Several techniques for storage of hydrogen are discussed in James A. Schwarz U.S. Pat. No. 4,716,736.
Other energy sources, such as methane, have looked attractive but they, too, have presented storage problems for practical use as a secondary energy source.
Recently, it has been observed that carbon adsorbents are much more effective if their pore geometries are related to the molecular dimension of the adsorbate, e.g., hydrogen or methane, and their sorbency is further enhanced if the pores are as uniform in geometry as possible. However, carbon structures have pore formations disposed randomly throughout and the pores tend to have random geometries. Consequently optimal storage of hydrogen, methane, or other gas in active carbon has not been achieved.